Bearing for indicator-shafts.



J. N. PERKINS.

BEARING FOR INDICATOR SHAFTS.

APPLICATION TILED 1 1111.13, 1911.

Patented Oct. 24, 1911.

IN VE IV TOR [77V 8858: P g fifl 5 1 er U716 64144141 11 UNITED STATES PATENT OFFICE.

JOHN NICHOLAS PERKINS, OF RICHMOND, VIRGINIA, ASSIGNOR TO RICHMOND SCALE 00., INCORPORATED, OF RICHMOND, VIRGINIA.

BEARING FOR INDICATOR-SHAFTS.

Specification of Letters Patent.

Patented Oct. 24, 1911.

To all whom it may concern:

Be it known that I, JOHN N. PERKINS, residing in Richmond, in the county of Hon rico and State of Virginia, have invented a new and Improved Bearing for Indicator- Shafts, of which the following is a specification.

My invention relates to certain new and useful improvements in bearings and it is more particularly designed for use as a bearing in connection with automatic computing scales and the like in which the scale or dial is carried by a rotatable shaft. The rotatable shaft in scales of this type is usually driven by a pull cable and counterweight. I have, however, designed a scale of this type in which the shaft is turned by a sector meshing with a pinion on the shaft. In a scale of this character considerable lateral thrust is provided. It is to provide a bearing that is especially adapted for this construction of scale that my present invention has been devised.

a This invention consists essentially in providing two rigid supports having vertical slots or openings of greater area than the cross sectional area of the shaft, through which supports the bearing ends of the shaft, that carries the indicator dial, projects. The bearing ends of the shaft rest on the stirrups which are swung from suit-able pivots and each has that surface which cont acts the shaft, curved on an arc whose cen ter is the pivot bearing of the stirrup, the length of the stirrup bearing surface being in excess of the circumference of the hearing portion of the shaft.

In its more subordinate nature, the invention includes those novel features of construction, combination and arrangement of parts, all of which will be first fully described, then be specifically pointed out in the appended claim and illustrated in the accompanying drawings, in which Figure 1, is a perspective view of a part of a scale embodying the invention. Fig. 2, is a detail elevation of one of the stirrups and bearings in the position the parts assume while the scale is at rest. Fig. 3, is a view similar to Fig. 2 showing the position of the parts when moving from zero position to weighing position. Fig. 4, is a detail vertical cross section of the device shown in Fig. 1. Figs. 5, 6, and 7 are face views of other forms of stirrups.

Referring now to the accompanying drawing, in which hke letters and numbers of reference indicate like parts in all the ards 8 and rests on the bearing surfaces 9| of the stirrups 10, one of which is at each end of the shaft, and the stirrups 10 have bearing portions 11 to rest on the knife edges 12, as clearly indicated in the drawing. The projecting portion of 5 of the shaft 5 is reduced slightly in diameter to leave a rounded shoulder 5 that prevents longitudinal movement of the shaft in its bearings by engaging the supports 8, should a tendency to longitudinal motion occur. It will also be observed that the area of the opening 7 in the supports is of greater width and length than the diameter of the shaft ends 5 so that the shaft ends 5 may hang freely in such opening 7 without contacting the walls thereof, when the scale is at rest or when the scale is turned to indicate the proper weight or value, and is vibrating at the limit of its movement just before coming to a rest so that there will be little or no friction between the shaft ends 5 and the standards 8.

When the scale is at rest, the parts are relatively positioned as indicated in Fig. 2 by reference to which it will be seen the knife edge bearing of the stirrup 10 is directly over the center of the shaft ends 5*. Now, when an article to be weighed is put on the scale pan (not shown) the gear sector 2 is turned in the direction of the arrow in Fig. 1 thus turning the pinion 4: in the direction of the arrow in Fig. 1, which imparts a lateral thrust from left to right in Fig. 3 which tends to move the shaft 5 bodily laterally. This movement is limited by contact between the shaft ends 5" and the walls of the openings 7 (see Fig. 3). As soon, however, as the movement of the pinion 4 has been started, the lateral thrust will reduce, gradually becoming m'l, thereby permreaches the limit of its movements and vibration ceases, the shaft ends 5 will rest in the opening 7 out of contact with the side walls thereof and directly beneath the knife edge 12 at which time the stirrups will be in a position similar to that indicated in Fig. 3 of the drawings.

If desired the sectors 10 may be counter weighted as at 13 (see Figs. 5 to 7 and instead of employing knife edge bearings 12 around bearing 12 (see Fig. 6) or a simple shaft like bearing 12 (Fig. 7) may be used.

It will be observed that by my construction of bearing extreme sensitiveness is obtained at the particular time at which it becomes most necessary, namely, at the time the scale with its goods arrives at its weight indicating position and the sector 2 oscillates or vibrates from side to side, coming to a rest at the proper indication.

From the foregoing taken in connection with the accompanying drawings, the complete construction, arrangement and advantages ofmy invention will be readily apparent.

What I claim is:

In a scale, a chart shaft, a gear sector carrying shaft, a pinion on said chart shaft and meshing with said gear sector whereby the motion of the gear shaft will be imparted to the chart shaft, a pair of relatively fixed supports having openings through which the ends of said chart shaft project, said chart shaft having reduced ends to leave shoulders, stirrups having curved bearing surfaces on which the ends of said chart shaft rest, said stirrup bearing surfaces being of greater length than the circumference of the shaft ends, pivot bearings on which said stirrups hang, the curvature of the bearing surface of said stirrups having as their radii the pivot bearing points.

JOHN NICHOLAS PERKINS.

Witnesses:

J. C. KENT, Ron'r. N. PoLLARo.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

